Photonic Crystal Simulation

Photonic crystals are periodic structures that are designed to affect the motion of photons in a similar way that periodicity of a semiconductor crystal affects the motion of electrons. The non-existence of propagating EM modes inside the structures at certain frequencies introduces unique optical phenomena such as low-loss-waveguides, omni-directional mirrors and others. The part of the spectrum for which wave propagation is not possible is called the optical band-gap.  The underlying physical phenomenon is based on diffraction. Therefore, the lattice constant of the photonic crystal structure has to be in the same length-scale as half the wavelength of the electromagnetic wave. Figure 1 shows a one dimensional periodic structure which is investigated by using the transient solver of CST MICROWAVE STUDIO® (CST MWS).

1 dimensional periodic structure
Figure 1: 1 dimensional periodic structure

The rods are made from GaAS with refractive index of 3.4 and with an edge length of about 180 nm. The lattice spacing between the rods is 760 nm. As a first step, the transmission of a plane wave through this crystal is simulated.

single column of the array
Figure 2: single column of the array

By using appropriate boundary and symmetry conditions it is sufficient to calculate a single column of this array as shown in Figure 2. In this case, the structure is driven by a waveguide port. Due to the magnetic and electric symmetry planes, the excitation mode is a  normally incident plane wave.

Transmisson vs. wavelength
Figure 3: Transmisson vs. wavelength

Figure 3 shows the transmission through the structure. Between 1400 and 2200 nm the transmission is zero. In this bandgap region no wave propagation in possible.

Wave Propagation at frequencies below the band gap
Figure 4: Wave Propagation at frequencies below the band gap

Figures 4-6 shows the propagation of a plane wave at normal incident for at different frequencies.

Wave propagation at frequencies in the band gap
Figure 5: Wave propagation at frequencies in the band gap

Wave Propagation at frequencies above the band gap
Figure 6: Wave Propagation at frequencies above the band gap

The information obtained about the photonic band gap can be used to design optical devices. Figure 7 shows the periodic PBG structure as described above. A line defect is introduced and the structure is excited with a electromagnetic wave at band gap frequencies. The wave can only propagate inside the line defect.

Photonic Crystal with line defect
Figure 7: Photonic Crystal with line defect

Finally, Figure 8 shows the wave propagation inside the Photonic crystal with a bent defect. Again, the structure is driven with a time harmonic signal. The signal frequency is inside band gap of the crystal. Consequently, the wave propagates inside bend defect.

Photonic crystal with a bend defect
Figure 8: Photonic crystal with a bend defect

This article demonstrates the possibilities to model photonic crystals with CST MWS by using the transient solver. The general characterization would also be possible with the Frequency Domain and Eigenmode Solver of CST MWS by applying periodic boundary conditions.

CST Article "Photonic Crystal Simulation"
last modified 15. Jan 2007 5:42
printed 24. Apr 2014 8:41, Article ID 296

All rights reserved.
Without prior written permission of CST, no part of this publication may be reproduced by any method, be stored or transferred into an electronic data processing system, neither mechanical or by any other method.


5 of 11 people found this article useful

Did you find this article useful?

Other Articles

Simulation of a compact antenna

Simulation of a compact antenna
This article demonstrates the simulation of an electrically large antenna. The design and numerical results are courtesy and permission of Chelton Antennas, France. The antenna operates at 8 GHz and was simulated using the CST MICROWAVE STUDIO® Transient Solver which is, as a result of its efficient memory scaling, ideal for such electrically large structures - the dish diameter in this example is approximately 20 wavelengths in size. Read full article..


CST STUDIO SUITE Brochure Document type
CST STUDIO SUITE 2014 is the culmination of years of research and development into finding the most accurate and efficient computational solutions for lectromagnetic (EM) designs. From static to optical, and from the nanoscale to the electrically large, CST STUDIO SUITE includes tools for the design, simulation and optimization of a wide range of devices. Analysis is not limited to purely EM effects, but can also include thermal and mechanical effects and circuit simulation. Read full article..

Light Trapping in Thin-Film Silicon Solar Cells with periodic Nano-Structures

Light Trapping in Thin-Film Silicon Solar Cells with periodic Nano-Structures
This article summarises the simulation study conducted with CST MICROWAVE STUDIO® (CST MWS) of thin-film silicon solar cells with nano-structured interfaces. The good agreement between the experimental data and solar cell simulations shows the reliability and versatility of the performed FIT simulations to investigate nano-optics of thin-film solar cell devices in 3 dimensions. This article is presented with the courtesy and permission of Hasse, C. and Stiebig, H. , Forschungszentrum Juelich who gave a presentation of their work at the CST European User group Meeting at Boppard, Germany, 9-10th March 2006. Read full article..

EMC simulation of consumer electronic devices

EMC simulation of consumer electronic devices
All consumer electronic devices need to meet EMC standards. By including EMC compliant design at an early stage, additional costly iterations can be avoided later on down the line. In this webinar we will present how board-level EMC design can significantly reduce emissions at their source. We will then focus on system level EMC, discussing different approaches of segmenting the system for an efficient simulation workflow. Finally we will analyze immunity, by demonstrating how different return current path configurations can affect performance of the device due to cable entry susceptibility. Read full article..

CST MWS Simulation of the SARAF RFQ 1.5 MeV/ nucleon proton/deuteron accelerator

CST MWS Simulation of the SARAF RFQ 1.5 MeV/ nucleon proton/deuteron accelerator Document type
J. Rodnizki, Soreq NRC - The SARAF RFQ is a four rod RFQ, operating at a frequency of 176 MHz, designed to bunch and accelerate a 4 mA deuteron/proton beam from 20 keV/nucleon DC up to 1.5 MeV/nucleon CW. Read full article..
Back Back  

Your session has expired. Redirecting you to the login page...